A memory device having a three-dimensional structure has been proposed in which a memory hole is made in a stacked body in which multiple electrode layers are stacked, and a charge storage film and a semiconductor film are provided to extend in the stacking direction of the stacked body in the memory hole. The memory device includes multiple memory cells connected in series between a drain-side selection transistor and a source-side selection transistor. The electrode layers of the stacked body are gate electrodes of the drain-side selection transistor, the source-side selection transistor, and the memory cells. A slit that reaches a substrate from the upper surface of the stacked body is made in the stacked body. A conductor is filled into the slit. For example, the conductor is used to form a source line. To reduce the cell size, it is effective to reduce the distance between the source line and the electrode layers. However, the distance between the source line and the electrode layers is determined by the electrical breakdown voltage between the source line and the electrode layers. Therefore, it is difficult to reduce the distance between the source line and the electrode layers unless the electrical breakdown voltage between the source line and the electrode layers can be increased. It is desirable to increase the electrical breakdown voltage between the source line and the electrode layers.